Canning foods has been an important part of food preservation and manufacturing since the invention by the British of tin cans for preserving meat for long sea voyages in 1812. Even after the advent and widespread use of other methods of food preservation such as freezing, the production of shelf-stable canned foods such as fish remains an important part of the food industry. Canned tuna and salmon, for example, represent 90% of the total fish packed in the United States.
In a typical process, fish, most of which have been frozen on the fishing vessel and held frozen in air until the cannery is approached, are thawed. They are eviscerated, precooked, cleaned, and the meat, sorted. Dark meat and trimmings are used for making pet food, meal and oil. The better fish fillets are cut and packed by machine as solid meat or chunks for human consumption. Filled cans pass down a line where salt and then oil or water are added, and the cans are heated, sealed, and retorted.
Similarly, canned meats are typically manufactured by heat processing to produce either pasteurized or shelf-stable products. The former must be held under refrigeration, as in the case of canned hams and picnics (pork shoulders). Shelf-stable canned meats are heated for a sufficient time to destroy most pathogens and can be cured without refrigeration. Common canned meat items include hams, luncheon meats, meat balls, Vienna sausage, and potted meat. Some of these are reacted with curing ingredients before being sealed in cans and heat-processed.
Because of differences in the food product, vegetable canning is slightly different. In vegetable canning, the vegetables are typically washed with chlorinated water to remove soil, stones, and other debris and to reduce the microbial population. Products are sorted, trimmed, peeled, and/or sliced according to specific need. Many products are then blanched, i.e., subjected to relatively mild heat treatment before packing into a container. Blanching serves as a final wash to reduce the microbial load, removing certain raw or off-flavors, and increases the pliability of the product to facilitate filling and permitting expulsion of dissolved or occluded gases from plant tissue. During blanching, the product is exposed to hot water or steam for several minutes and then immediately put into containers and packed in salt brine or syrups to cover. Filled containers are generally exhausted by being passed through a hot water bath or steam chamber to expel gas and expand the product before the can is sealed.
Unlike vegetables, which ordinarily require pressure-cooker processing up to about 250E C. to inactivate spores of Clostridium botulinum that may grow in foods stored at room temperature and neutral pH's, many fruits naturally possess sufficient acidity to permit thermal preservation at lower, i.e., boiling water temperature, before canning. Fruits are prepared by washing, sorting, and trimming. Specialized preparation may be required for some fruits, such as stem and pit removal for cherries and peel and core removal for apples. Sliced or prepared fruit may require blanching to remove tissue gases prior to filling. Aggregate fruit products such as whole berries or sliced portions may be canned in water or sugar syrups. Filled containers are exhausted by thermal or vacuum within the container upon cooler. Sealed containers are typically heated in water or atmospheric steam to about 200E F. in the container center prior to cooling.
The inventor has observed that almost all canned food products are stored in some kind of packing fluid that is an oil, brine, syrup, fruit or vegetable juice, or the like, or mixtures of these. Removing this fluid has been the source of mess and frustration since the advent of the tin can.
When canned food products are opened, it is common practice to partially or fully drain off the packing fluid before eating the foodstuff or using it in a recipe. Indeed, many recipes such as those calling for tuna or spinach require that the foodstuff be completely wrung out to remove as much of the packing fluid as possible.
For example, tuna is usually advertised as being water or oil packed. This would seem to indicate that the liquid is only around the tuna. If this were the case, the user could simply hold the severed lid against the contents and pour the liquid off. The fact is most of the liquid is retained within the tuna itself. Most people squeeze out the liquid by first opening the can and then pushing the severed lid down in the can with their fingers or thumbs while holding the can upside down. This procedure exerts forces on the lid primarily at the two finger engaging points. This causes the thin lid to bend which obviously applies an uneven pressure against the tuna. A good share of the juice thus still remains within the tuna. This is particularly so with persons with weak hands. The two point uneven pressure can also cause the edges of the lid to bend up and be a source of injury to the user. Also, pressing of the liquid from the can in the above manner not only exposes the fingers to the odorous contents but unless precise even pressure is applied the lid frequently sticks in the can. Furthermore getting the lid out of the can after pressing is time consuming and can result in injury.
A number of devices have been suggested for draining off, and in some cases squeezing out, packing fluid from a canned food product. Whether the can is opened with a can opener or a key, or the can is a glass jar with a lid, a common means of accomplishing this is to use the lid as a press. After opening the can around its edge, the can is tipped and fluid, decanted. If more fluid is to be removed, the lid is pushed down on the can contents while the can remains tipped. Because of the geometry of the can lid, however, this procedure is messy because the only way packing fluid can escape is around the lid. Packing fluid typically squirts out all round the lid, and on the hand and often down the arm of the person holding the tipped can.
Furthermore, some people, especially the elderly, may have trouble controlling these can squeezing devices. These people may not be able to generate sufficient pressure to totally remove all of the fluid from the can, and may subject their hands to danger by placing them near the ragged edges of the can to remove liquid that the press leaves.
Therefore, there is a need for a device that can efficiently remove liquid from a can containing food packed in liquid and which a person with limited hand strength can easily use to fully remove fluid from the can.
Still further, many cans come in various sizes. For example, some tuna is sold in single-serving size cans while other tuna is sold in larger sizes. To be effective, a press should fit the can; however, a press sized to fit a large can will not fit a small can, and a press sized to fit a small can may not be efficient when used with a large can.
Therefore, there is a need for a device that can remove liquid from a can containing food packaged in liquid which is adaptable to various sizes of cans.